// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_ADDRESS_MAP_H_
#define V8_ADDRESS_MAP_H_

#include "include/v8.h"
#include "src/assert-scope.h"
#include "src/base/hashmap.h"
#include "src/objects/heap-object.h"
#include "src/roots.h"

namespace v8 {
namespace internal {

    template <typename Type>
    class PointerToIndexHashMap
        : public base::TemplateHashMapImpl<uintptr_t, uint32_t,
              base::KeyEqualityMatcher<intptr_t>,
              base::DefaultAllocationPolicy> {
    public:
        typedef base::TemplateHashMapEntry<uintptr_t, uint32_t> Entry;

        inline void Set(Type value, uint32_t index)
        {
            uintptr_t key = Key(value);
            LookupOrInsert(key, Hash(key))->value = index;
        }

        inline Maybe<uint32_t> Get(Type value) const
        {
            uintptr_t key = Key(value);
            Entry* entry = Lookup(key, Hash(key));
            if (entry == nullptr)
                return Nothing<uint32_t>();
            return Just(entry->value);
        }

    private:
        static inline uintptr_t Key(Type value);

        static uint32_t Hash(uintptr_t key) { return static_cast<uint32_t>(key); }
    };

    template <>
    inline uintptr_t PointerToIndexHashMap<Address>::Key(Address value)
    {
        return static_cast<uintptr_t>(value);
    }

    template <>
    inline uintptr_t PointerToIndexHashMap<HeapObject>::Key(HeapObject value)
    {
        return value.ptr();
    }

    class AddressToIndexHashMap : public PointerToIndexHashMap<Address> {
    };
    class HeapObjectToIndexHashMap : public PointerToIndexHashMap<HeapObject> {
    };

    class RootIndexMap {
    public:
        explicit RootIndexMap(Isolate* isolate);

        // Returns true on successful lookup and sets *|out_root_list|.
        bool Lookup(HeapObject obj, RootIndex* out_root_list) const
        {
            Maybe<uint32_t> maybe_index = map_->Get(obj);
            if (maybe_index.IsJust()) {
                *out_root_list = static_cast<RootIndex>(maybe_index.FromJust());
                return true;
            }
            return false;
        }
        bool Lookup(Address obj, RootIndex* out_root_list) const;

    private:
        HeapObjectToIndexHashMap* map_;

        DISALLOW_COPY_AND_ASSIGN(RootIndexMap);
    };

} // namespace internal
} // namespace v8

#endif // V8_ADDRESS_MAP_H_
